Aircraft control



S. WEBSTER 2,298,523

AIRCRAFT CONTROL Oct. 13, 1942.

Filed Oct. 21; 1940 spmu za MOTOR WHEEL FLEM- TIME s mmuc, BRAKING V I s 0 U5 3 0 nssczu-r Accusmmnu v C I vide means to start controlling the deceleration of Patented Oct. 13, 1942 EQE 2,298,523 AIRCRAFT CONTROL Sidney H. Webster,

Bogota, N. J., assignor to- Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application October 21, 1940, SerialNo. 362,173

3 Claims.

This invention relates to aircraft appliances and particularly to appliances which facilitate smooth and safe landing of an aircraft.

The invention is herein shown as applied to an airplane of a type requiring tired-wheels as the ground contacting portion of the landing gear;

but it is to be understood that in its broadest aspects this invention type of aircraft having a landing gear.

The large tire of an airplane wheel takes severe punishment when the plane lands, due to the fact that it must, theoretically, assume a speed of rotation corresponding to the landing speed of-the ship. The wheels, weighing in some cases-six hundred pounds each, and having a large moment of some time before the result is stripped or bumed off the tire at each landing. This action is especially severe when landing on concrete runways.

An object of the present invention is to prothe wheels rotating prior to landing, such that their speed is nearly proportional to the landing speed of the plane.

A second object is to provide means for gradual reaching the proper speed, and

is applicable to any other inertia, are forced to slip for that large pieces of rubber are being shown in Fig. 1.

deceleration of the wheels, after first contact with the ground, to the end that the craft may be smoothly retarded as it moves along the ground; the wheels remaining in motion during such retardation, wherefore the wear and tear on the rubber is almost entirely eliminated.

A further object is to provide unitary means for doing both these jobs in proper sequence; that is, for starting the wheels (accelerating them to a speed consonant with that of the plane at the moment of contact) and for subsequently said wheels, and thus controlling deceleration of the craft itself.

These and other objects will become apparent upon inspection of the following specification and the accompanying dra I wherein is illustrated the preferred embodiment of the invention. It is to be expressly understood, however, that the drawing is intended merely to serve as an illustration of one mode of embodying the invention in a practical form and is not designed as a definition of the limits of the invention.

In the drawing:

Fig. 1 is a vertical axial sectional view through the hub of one of the wheels of an aircraft landing gear, showing the invention applied thereto;

Fig. 2 is a diagram showing th currently preferred electrical control means;

43 are mounted, as shown Fig. 3 is a diagram showing the time-speed relationship, and sequence of actions; and

Fig. 4 is a diagram showing'the invention applied to both wheels of a landing gear.

Referring to the drawing, the invention is shown embodied in a landing gear-including a pair of rubber tired wheels 5 of which is rotatableupon bearings ll (Rig. 1) surrounding stationary tubes or axles I and 8, forming parts of diagonal braces 9 and I0, respectively; the latter being tied into the fuselage of the plane as indicated at l2, and through the usual shock-absorbing means, as indicated at 13. Extending through each tube or axle 1-8 is a rod It, said rods being pivotally connected to- !5; andoperator of the craft, and serving when drawn taut by the operator to move the rods 14 outwardly through the wheels 5 and 8.

Associated with each wheel, 5 and 6, is an assembly of parts which is identical for each wheel; only the assembly for wheel 6, however, This assembly includes a cup-shaped hub cap 26 having an outer portion 21 on which are mounted bell cranks 28 whose weights 29, integrated therewith, swing outwardly in response to the centrifugal force exerted thereon whenever the wheel assembly (6-26-21) is rotated. weights are held'in the action of spring 3! upon collar 32; the inner end of spring 3! abutting the hub-sleeve 33 of the wheel assembly.

Within spring 3! there extends a plunger 36 having a pair of circumferential grooves 38 and 39-the groove 38 being registrable with spring pressed detents 4! when the plunger is pressed inwardly, and the groove 39 being engaged by fingers 40 of cam elements 42 which operatively abutarms 43 of the brake assembly.

at Mi, upon the cups shaped brake housing 41, the latter being carried by the circular extension 48 of the gear housing 49. Gear housing 49 also carries the outer, or orbital gear 5! of a planetary system whose central, or sun gear one-way driving means for-the hydraulic clutch 58-51-58 of the fluid flywheel" type that is now in extensive use in automobile transmission systems.

The brake shoes 44 are movable to engage the inner circular surface and 6 (Fig. 4) each When not rotating, the positions shown by the These arms 52 is an integral part of the (on the brake arms 43) with the motors 85-and also,

45 of the outer element 58 and said outer element 58 tion 8| to receive the screws 82 which carry the planets 83 of the gear train. One of the two electric motors 85 (diagrammatically shown in Fig. 2) drives this gear train of wheel 8, while the other drives the corresponding gear train (not shown) of wheel 5. In each case the drive to the gear train is uni-directional, the structure for this purpose being preferably a roller type clutch in each motor drive, with an outer driving race 88 integrated with extension 81 of the motor armature shaft, and an inner (driven) race 88 as an integral part of a shaft 89 having teeth 52 to constitute the sun gear of the planetary system, heretofore described. Shaft 89 extends into the hub H of driven element 58 of the fluid clutch, and is centrally bored to the rods l4 heretofore described. The hub 'II is slotted for passage therethrough of brake-actuating fingers 4B, and extends outward into driving relationship to hub cap 28, to which it is secured by the same screws 18 which hold the hub-sleeve 33 heretofore described. Ball-bearings 14 facilitate relative rotation between elements S'Iand 58 of the fluid clutch, and bearings 18 act similarly as between, element 58 and shaft 89. The frame tube, or axle, 8 encloses the motor 85 and connects at its inner end. with gear housing 49, to support the latter. Fastening means 10' secures part 58 to part 51 of the fluid clutch.

A switch element 8| (Fig. 2) controls the energization of the two motors 85, and may be operated by a governor mechanism so as to move into bridging relationship to a pair of contacts 83 when the aircraft engines decelerate preparatory to descent of the craft. These contacts 83 are shown as adapted to connect source 82 if desired, with a landing gear motor, 85-to produce enerigzation of said motors as the craft begins its descent; the energizing process continuing until the flow of current is interrupted by the action of circuit breaker 90 in moving contact 88 out of engagement with contacts 81 and 88. This will occur as the landing gear reaches fully extended position, that is, at the approximate moment of contact with the ground. The motor driven wheels 8, at that moment, will have been accelerated to, say, 200 R. P. M (see point A on the Fig. 3 diagram) by reason of the drive from motors 85 and the associated reduction gearing, previously described. The ensuing travel of the plane along the landing fleld runway will accelerate the wheels to, say, 300 R. P. M. (point B on the diagram) and-assuming a proper pre-setting of spring 3|, by adjustment of nut 32-the developed centrifugal force will then be effective to move element 38 to the left sufficiently to throw brake shoes 44 into contact with the inner surface 45 of the fluid clutch element 58-51. When this occurs, fluid clutch element 5851 will begin to act as a fluid brake with respect to fluid clutch element 58, thereby gradof the fluid clutch, also has a hub porually decelerating 'the said element 58 and the receive one of automatic means shown converting said clutch parts which rotate therewith-sai d parts including member 28 and wheel 8. Wheel 5 will be simultaneously decelerated (portion B to C of the diagram, Fig. v3) by the similar action of the duplicate fluid brake associated therewith. Thus the craft will be brought to a gradual stop.

During the A-B period of wheel acceleration-the motors 85 being then-deenergizedclutch member 88 (and the corresponding member of the other wheel assembly) will over-run clutch member 88, thus leaving the motors 85 free to come to rest. After complete stoppage of the craft, the brake actuating cams 42 may be moved back to the inoperative position (shown in Fig. l) by a pull of the operator exerted on cables 11, whereupon the brake releasing springs (not shown, but see the comparable brake releasing springs H5, H8 in Fig. 2 of Lansing Patent No. 1,973,288) will return brake shoes 44 to the released position shown in Fig. 1. The craft is then ready for its next flight.

During take-off, in order to guard against an automatic re-application of the brake, the rods M will be held advanced (that is, in the position to the right of that shown in Fig. 1) by continuous pull on cables II, or by latching the ends of said cables in the pulled-up position, by suitable latching means, not shown.

The circuit to motors 85 may, of course, be closed and/or opened, normally, in lieu of the in Fig. 2.

What is claimed is:

1. In combination with an aircraft wheel, rotating means for said wheel, said rotating means comprising a motor and fluid clutch. means for to a fluid brake for deceleration of the wheel after de-energization of the motor, said converting means including friction elements engageable with a part of said fluid clutch, and speed responsive means for moving said friction elements to engaging position.

2. In an aircraft having a landing gear movable from a position of retraction to a position of full extension, and including a rotatable wheel,

- means for movingsaid landing gear, including said wheel, to said position of full extension,

'rotating means for said wheel, said rotating 1 able from a position of retraction motor.

means comprising a motor and a fluid clutch, means for energizing said motor as the craft prepares to land. and means responsive to a full extension of the landing gear to de-energize said a landing gear movto a position of full extension, and including a rotatable wheel, means for moving said landing gear, including said wheel, to said position of full extension, rotating means for said wheel, said rotating means comprising a motor and a fluid clutch, means responsive to deceleration'of the aircraft engines for energizing said motor as the craft and means responsive to a full gear to de-energize said 3. In an aircraft having motor.

SIDNEY Il WEBSTER. 

